Central processing complexes made up of a plurality of processors and associated hardware may be configured through logical partitioning into one or more groups of cooperating system images. Cooperating system images across multiple logical partitions within a single central processor complex (CPC) or across multiple CPCs can be grouped together for a common general purpose into an entity called a sysplex. The system images within a sysplex may share common physical resources. As time passes, it is becoming necessary to group together cooperating system images within a single CPC for different specific purposes as opposed to the general sharing of resources that occurs in a sysplex. Hence, a mechanism is needed to create and identify different types of collections of cooperating system images.
A group of system images, or sysplex, communicates with external devices over one or more channels to a control unit which is connected to the external device. There exists a method of assigning channels to a group of logical partitions. The user can set an existing PARTITION keyword in the input/output configuration program (IOCP) or implement a similar function in the hardware configuration definition (HCD) program. By doing this, the user can explicitly specify which logical partitions may access a specific channel.
One problem with this approach is that it requires the user to associate the channel with a specific set of partitions and if the partition is later assigned to another group, the user is responsible for changing the PARTITION keyword to change the resource to partition associations. If the user does not do this, then there is risk that a partition could lose its last channel to a control unit. In addition, the user could assign non-cooperating groups to the same channel path, exposing the system to errors, data corruption and loss of availability.
An exemplary embodiment of the invention is a method for creating and identifying different kinds of groups of cooperating system images within a single machine, a single central processor complex (CPC) where each kind of group has a different functional purpose. Such a collection of cooperating system images is referred to as a logical partition cluster (LPC). An LPC is created or identified using a diagnose instruction. The diagnose instruction includes a subcode field designating a function to be performed and a logical partition cluster type field indicating the type of logical partition cluster said function is to be performed on.
Another exemplary embodiment of the invention is a method for assigning resources in a system configurable into logical partition clusters. The method includes defining at least one logical partition cluster having at least one system image. An LPC name index record storing an LPC name index for each of a plurality of resources is provided. The LPC name index record is indexed by a resource identifier. An LPC name record storing at least one LPC name is also provided. At least one LPC name index points to an LPC name in the LPC name record and each LPC name identifies a logical partition cluster. A resource is assigned to a logical partition cluster in response to the LPC name index record and the LPC name record.